.TH std::chrono::day::operator+=,std::chrono::day::operator-= 3 "2024.06.10" "http://cppreference.com" "C++ Standard Libary"
.SH NAME
std::chrono::day::operator+=,std::chrono::day::operator-= \- std::chrono::day::operator+=,std::chrono::day::operator-=

.SH Synopsis
   constexpr std::chrono::day& operator+=( const std::chrono::days& d \fB(1)\fP \fI(since C++20)\fP
   ) noexcept;
   constexpr std::chrono::day& operator-=( const std::chrono::days& d \fB(2)\fP \fI(since C++20)\fP
   ) noexcept;

   Adds or subtracts d.count() days from the day value.

   1) Equivalent to *this = *this + d;.
   2) Equivalent to *this = *this - d;.

.SH Return value

   A reference to this day after modification.

.SH Notes

   If the result would be outside the range [0, 255], the actual stored value is
   unspecified.

.SH Example


// Run this code

 #include <cassert>
 #include <chrono>

 int main()
 {
     std::chrono::day d{15};

     d += std::chrono::days(2);
     assert(d == std::chrono::day(17));

     d -= std::chrono::days{3};
     assert(d == std::chrono::day(14));
 }

.SH See also

   operator++
   operator++(int) increments or decrements the day
   operator--      \fI(public member function)\fP
   operator--(int)
   operator+       adds or subtracts a number of days and a day, or find the difference
   operator-       between two days
   (C++20)         \fI(function)\fP
